Fix issue 158:

To be able to share the SQL token cache between apps, the `DataProtection` must share the same application name.

Author: Tiago Brenck

4-WebApp-your-API/Client/Controllers/TodoListController.cs

@@ -1,5 +1,6 @@
 using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Identity.Web.Client;
 using System.Collections.Generic;
 using System.Threading.Tasks;
 using TodoListClient.Services;
@@ -18,6 +19,7 @@ public TodoListController(ITodoListService todoListService)
         }
 
         // GET: TodoList
+        //[MsalUiRequiredExceptionFilter(ScopeKeySection = "TodoList:TodoListScope")]
         public async Task<ActionResult> Index()
         {
             return View(await _todoListService.GetAsync());

Microsoft.Identity.Web/Client/TokenCacheProviders/Sql/MSALAppSqlTokenCacheProviderExtension.cs

@@ -90,7 +90,10 @@ public static IServiceCollection AddSqlPerUserTokenCache(this IServiceCollection
             //var tokenCacheDbContext = new TokenCacheDbContext(tokenCacheDbContextBuilder.Options);
             //tokenCacheDbContext.Database.EnsureCreated();
 
-            services.AddDataProtection();
+            // To share protected payloads among apps, configure SetApplicationName in each app with the same value. 
+            // https://docs.microsoft.com/en-us/aspnet/core/security/data-protection/configuration/overview?view=aspnetcore-2.2#setapplicationname
+            services.AddDataProtection()
+                .SetApplicationName("WebApp_Tutorial");
 
             services.AddDbContext<TokenCacheDbContext>(options =>
                 options.UseSqlServer(sqlTokenCacheOptions.SqlConnectionString));